An air conditioner is a device that is placed in a house, an office, a shop, a green house, or the like and maintains indoor environment to be pleasant for people to live or to be suitable for crops to be grown by adjusting temperature, humidity, cleanliness and air flow.
Recently, a multi-air conditioner system has been widely used, where a plurality of indoor units are connected to a single outdoor unit, since buildings have become large and there has been an attempt to reduce spaces for an outdoor unit.
Typically, the multi-air conditioner system may include an outdoor unit, a plurality of indoor units which are connected to the outdoor unit in parallel and a cooling and heating conversion device which is disposed between the outdoor unit and the plurality of indoor units and converts cooling and heating.
In such the conventional multi-air conditioner system, a means for inputting which indoor unit is connected to each branch hole of a cooling and heating conversion device has been required. Specifically, a rotary switch for inputting the number of branch hole connected to each indoor unit or the number of indoor unit connected to each branch hole has been used as a means for inputting which indoor units is connected to each branch hole.
However, since an installation engineer memorizes the address of an indoor unit connected to each branch hole and manually inputs the address at the time of installing the indoor unit, errors may be caused by falsely inputting the address, or air conditioning may not be performed in the way a user intend. In addition, only one indoor unit may be connected to a single branch hole, and thus a plurality of indoor units are not connected to a single branch hole.